Cooling device for electronic instrument and electronic instrument

ABSTRACT

A cooling device contained in a casing unit of a computer includes a compressor, a condenser, an evaporator, a capillary tube functioning as expanding means, and a blower fan. These components constituting the cooling device are connected to one another by tubular pipes. Moreover, in the present invention, the compressor, the condenser, and the blower fan are placed at two-dimensionally different positions, and longitudinal directions of the condenser and the compressor are placed in an L shape in a vicinity of the blower fan. With this configuration, a two-dimensional size of the cooling device can be made compact, so that the cooling device would not limit a layout of other components contained in the casing unit.

Priority is claimed to Japanese Patent Application Number JP2005-286813 filed on Sep. 30, 2005, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a cooling device for an electronic instrument and an electronic instrument. In particular, the present invention relates to a cooling device for an electronic instrument in which a refrigeration cycle is used and an electronic instrument.

2. Description of the Related Art

In recent years, notebook computers have evolved significantly to have more enhanced functionalities and to be smaller in size. With enhancement of functionalities of notebook computers, central processing units (CPUs) are becoming faster and more versatile, and thereby, the amount of heat generated in each of the CPUs has been increasing.

Accordingly, heretofore, for the purpose of reducing a temperature rise of a CPU, a radiating fin excellent in heat dissipation has been attached to a surface of the CPU, and air has been blown on the radiating fin by a rotating blower fan. In addition, after heat transported by using a heat pipe, the heat has been dissipated by the radiating fin. By taking such countermeasures, for example, a temperature rise of a CPU approximately equivalent to that caused by a power consumption of 60 W can be reduced, thereby making the maximum temperature of the CPU approximately 70° C. or less.

However, the amount of heat generated in each of recent CPUs is increased approximately to that caused by the power consumption of 100 W, for example. This has caused a problem that the CPU cannot be sufficiently cooled by the above-described heat dissipation methods by using the blower fan and the heat pipe. Furthermore, even if the CPU can be sufficiently cooled, there has been a problem that a cooling device for cooling the CPU becomes very large.

Other methods of reducing a temperature rise in the CPU also include a method using a water-cooling cycle and a method using a refrigeration cycle. These methods can cool the CPU more efficiently than the aforementioned methods using the blower fan. Thereby, the temperature of the CPU in which a large amount of heat is generated can be maintained at a certain temperature or less. Japanese Patent Application Publication No. 2002-198478 discloses technical matters for cooling a semiconductor device by using a refrigeration cycle.

However, the above-described cooling device using a refrigeration cycle has a complicated structure. For this reason, there is a problem that the cooling device is difficult to be incorporated in a small-size notebook computer. Specifically, the cooling device using a refrigeration cycle requires a compressor for compressing a refrigerant, an evaporator for taking in heat from a radiator, a condenser for taking heat out of the refrigerant, expanding a device for expanding the refrigerant, a blower fan and the like. On the other hand, in a notebook computer, a large number of electronic components such as a hard disk drive (HDD) and a disk drive need to be contained in a small-size casing, and thereby, a space usable for a cooling device is limited. Accordingly, it has been difficult to contain a cooling device using a refrigeration cycle, which requires a large number of components, in a casing of a small-size notebook computer.

Moreover, in the cooling device using the refrigeration cycle, since heat is taken out of a high-temperature compressed refrigerant by using a fan, a temperature of air exhausted from the cooling device is as high as, for example, approximately 50° C. to 60° C., or more than that. If a user using a computer touches such high-temperature air, the user is likely to get burned. Thus, there has been a problem that the air exhausted from the cooling device cannot be exhausted in an arbitrary direction.

SUMMARY OF THE INVENTION

The present invention has been accomplished in view of the above-described problems. A main object of the present invention is to provide a small-size cooling device in which a refrigeration cycle is used and an electronic instrument.

A cooling device for an electronic instrument of the present invention includes: compressing means which compresses a refrigerant; condensing means which condenses the refrigerant compressed by the compressing means into a liquid by releasing heat from the refrigerant to an outside; expanding means which expands the refrigerant condensed into the liquid by the condensing means; evaporating means which evaporates the refrigerant expanded by the expanding means by receiving heat from a semiconductor element; and blowing means which blows air. The compressing means and the condensing means are placed at two-dimensionally different positions. Longitudinal directions of the condensing means and the compressing means are placed in an L shape.

A cooling device for an electronic instrument of the present invention includes: compressing means which compresses a refrigerant; condensing means which condenses the refrigerant compressed by the compressing means into a liquid by releasing heat from the refrigerant to an outside; expanding means which expands the refrigerant condensed into the liquid by the condensing means; evaporating means which evaporates the refrigerant expanded by the expanding means by receiving heat from a semiconductor element; and blowing means which blows air. The compressing means, the condensing means, and the blowing means are placed at two-dimensionally different positions. The compressing means and the condensing means are placed in a vicinity of the blowing means.

A cooling device for an electronic instrument of the present invention includes: compressing means which compresses a refrigerant; condensing means which condenses the refrigerant compressed by the compressing means into a liquid by releasing heat from the refrigerant to an outside; expanding means which expands the refrigerant condensed into the liquid by the condensing means; and evaporating means which evaporates the refrigerant expanded by the expanding means by receiving heat from a semiconductor element. At least a portion of a pipe connected to the evaporating means is positioned above the evaporating means.

A cooling device for an electronic instrument of the present invention includes: compressing means which compresses a refrigerant; condensing means which condenses the refrigerant compressed by the compressing means into a liquid by releasing heat from the refrigerant to an outside; expanding means which expands the refrigerant condensed into the liquid by the condensing means; and evaporating means which evaporates the refrigerant expanded by the expanding means by receiving heat from a semiconductor element. The compressing means, the condensing means, and the evaporating means are placed at different positions on one plane. The compressing means includes a rotary compressor placed horizontally on the one plane. The rotary compressor includes an inlet section through which the refrigerant is introduced, and an outlet section through which the refrigerant is discharged. The outlet section is provided above a rotation axis of the rotary compressor.

A cooling device for an electronic instrument of the present invention includes: compressing means which compresses a refrigerant; condensing means which condenses the refrigerant compressed by the compressing means into a liquid by releasing heat from the refrigerant to an outside; expanding means which expands the refrigerant condensed into the liquid by the condensing means; and evaporating means which evaporates the refrigerant expanded by the expanding means by receiving heat from a semiconductor element. The compressing means, the condensing means, and the evaporating means are placed at different positions on one plane. The compressing means includes a rotary compressor placed horizontally on the one plane. The rotary compressor includes an inlet section through which the refrigerant is introduced, and an outlet section through which the refrigerant is discharged. The inlet section is provided below a rotation axis of the rotary compressor.

An electronic instrument of the present invention has a casing unit containing a functional element which operates while generating a heat. The electronic instrument includes a cooling device contained in the casing unit. The cooling device cools the functional element by using a refrigeration cycle.

An electronic instrument of the present invention has a casing unit containing a functional element which operates while generating heat. The electronic instrument includes a cooling device contained in the casing unit. The cooling device includes compressing means which compresses a refrigerant, condensing means which condenses the refrigerant compressed by the compressing means into a liquid by releasing a heat from the refrigerant to an outside, expanding means which expands the refrigerant condensed into the liquid by the condensing means, evaporating means which evaporates the refrigerant expanded by the expanding means by receiving a heat from a semiconductor element, and blowing means which blows air. Longitudinal directions of the condensing means and the compressing means are placed approximately parallel respectively to side faces of the casing unit.

An electronic instrument of the present invention has a casing unit containing a functional element which operates while generating heat. The electronic instrument includes a cooling device contained in the casing unit. The cooling device includes: compressing means which compresses a refrigerant; condensing means which condenses the refrigerant compressed by the compressing means into a liquid by releasing heat from the refrigerant to an outside; expanding means which expands the refrigerant condensed into the liquid by the condensing means; evaporating means which evaporates the refrigerant expanded by the expanding means by receiving heat from a semiconductor element; and blowing means which blows air. The electronic instrument further includes monitoring means which monitors a temperature of the functional element, and controlling means which controls a level of cooling performance of the cooling device based on an output from the monitoring means.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a plan view showing a computer according to an embodiment of the present invention, and FIG. 1B is a plan view showing a cooling device according to the embodiment of the present invention.

FIG. 2A is a perspective view showing the cooling device according to the embodiment of the present invention, and FIG. 2B is a perspective view of the computer according to the embodiment of the present invention as seen from below.

FIG. 3A is a view of the computer according to the embodiment of the present invention as seen from front, and FIG. 3B is a cross-sectional view of a portion in which the cooling device is provided.

FIG. 4A is a plan view of a rotary compressor according to the embodiment of the present invention, and FIG. 4B is a cross-sectional view thereof.

FIGS. 5A and 5B are plan views showing cooling devices according to embodiments of the present invention, respectively.

FIG. 6 is a view showing an electrical configuration of a cooling device according to an embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. This embodiment of the present invention will be described by taking a notebook computer as an example of an electronic instrument. However, this embodiment can also be applied to other electronic instruments. For example, this embodiment can also be applied to a desktop computer, a personal digital assistant (PDA) and the like.

FIGS. 1A and 1B are views showing a notebook computer 10 (hereinafter abbreviated as a computer) of this embodiment. FIG. 1A is a plan view of the computer 10 as seen from above, and FIG. 1B is a plan view showing a cooling device 40 incorporated in the computer 10.

Referring to FIG. 1A, the computer 10 of this embodiment includes a casing unit 30 and a display unit 20. The casing unit 30 contains a heat-generating functional element such as a CPU 36, and the display unit 20 is rotatably connected to the casing unit 30.

The display unit 20 includes a display such as a liquid crystal display or an organic electro luminescence (EL) display.

The casing unit 30 contains electronic components constituting the computer 10. Specifically, the casing unit 30 contains a mother board 31, a compact disc (CD) ROM drive 32, a battery 33, an HDD 34, a floppy disk drive (FDD) 35, the cooling device 40, the CPU 36 and the like. These components contained in the casing unit 30 are placed at two-dimensionally different positions. Furthermore, in addition to these, a PC card reader, a semiconductor memory, cables for connecting these to each other, and the like are contained in the casing unit 30. Among the electronic components contained in the casing unit 30, it is the CPU 36 that generates a particularly large amount of heat. The cooling device 40 is provided in order to dissipate the heat of this CPU 36.

A size of the upper face of the display unit 20 is approximately equal to that of the casing unit 30. The display unit 20 and the casing unit 30 are folded to face each other, thereby collectively constituting one casing. When the casing unit 30 and the display unit 20 are folded, a size of the upper face of the computer 10 is, for example, A4 size (210 mm×290 mm) or BS size (182 mm×257 mm). Moreover, although not shown here, a keyboard and a pointing device such as a pad are placed in the upper face of the casing unit 30.

Referring to FIG. 1B, a constitution of the cooling device 40 will be described. The cooling device 40 includes a compressor 41 (compressing means), a condenser 42 (condensing means), an evaporator 44 (evaporating means), a capillary tube 43 (expanding means), and a blower fan 45 (blowing means). These units constituting the cooling device 40 are connected to one another by tubular pipes 46.

The compressor 41 has a function of compressing a refrigerant introduced. The refrigerant is made of ammonia, chlorofluorocarbon, carbon dioxide and the like. As the compressor 41, a rotary compressor or a reciprocating compressor is employed. In this embodiment, a rotary compressor horizontally placed is employed as the compressor 41. A rotary compressor is relatively small and therefore suitable for the compressor 41 incorporated in the notebook computer. Details of the compressor 41 will be described later.

The compressor 41 further includes an inlet section 48 through which the refrigerant is introduced from an outside, and an outlet section 47 through which the refrigerant compressed inside the compressor 41 is discharged to the outside. In this embodiment, the outlet section 47 of the compressor 41 is placed at a position closer to the condenser 42 than the inlet section 48. With this placement, the outlet section 47 of the compressor 41 and the condenser 42 come close to each other. Accordingly, the refrigerant compressed by the compressor 41 can be immediately supplied to the condenser 42.

Note that, the outlet section 47 does not necessarily need to be placed at a condenser 42 side. The position of the outlet section 47 may be changed depending on a constitution of the compressor 41. That is, the outlet section 47 may be placed farther away from the condenser 42 than the inlet section 48. In this case, the outlet section 47 is provided at a lower portion, in the drawing, than the inlet section 48 in the compressor 41.

Here, the compressor 41 is placed in a left side portion (in a vicinity of the left end) of the inside of the casing unit 30 in a manner that the longitudinal direction of the compressor 41 is approximately parallel to a left side face of the casing unit 30. However, this placement can be changed. That is, the compressor 41 may be placed in a right side portion (in a vicinity of the right end) of the inside of the casing unit 30 in a manner that the longitudinal direction of the compressor 41 is parallel to a right side face of the casing unit 30.

The condenser 42 has a function of causing the refrigerant compressed by the compressor 41 to release heat to the outside, thereby condensing the refrigerant into liquid. The condenser 42 is formed of a plurality of metal plates placed in parallel to each other. The metal plates constituting the condenser 42 are thermally coupled to the pipe 46 through which the refrigerant passes. In the drawing, the condenser 42 is placed in a vicinity of a rear end portion of the inside of the casing unit 30 in a manner that the longitudinal direction of the condenser 42 is approximately parallel to a rear side face of the casing unit 30. However, this placement can also be changed. That is, the condenser 42 may be placed in the left side portion (in the vicinity of the left end) or the right side portion (in the vicinity of the right end) of the inside of the casing unit 30 in a manner that the longitudinal direction of the condenser 42 is parallel to the left or right side face of the casing unit 30.

The capillary tube 43 has a function of expanding the refrigerant. Here, the capillary tube 43 wound in a circle is placed on the blower fan 45. By placing the capillary tube 43 on the blower fan 45, a two-dimensional size of the cooling device 40 can be reduced.

The evaporator 44 is thermally coupled to the heat-generating electronic component such as the CPU 36. Accordingly, the evaporator 44 receives the heat generated in the CPU 36, and thereby the refrigerant is changed from a liquid state to a gaseous state in the evaporator 44. Here, the evaporator 44 is placed so as to be superposed on the CPU 36.

The blower fan 45 has a function of taking in low-temperature air from the outside of the casing unit 30 and blowing this low-temperature air on the condenser 42 and the compressor 41. The air heated to a high temperature by receiving the heat from the condenser 42 and the compressor 41 is expelled to the outside from the side faces of the casing unit 30.

An operation of the cooling device 40 constituted as described above is as follows. When the cooling device 40 starts operating in order to cool the CPU 36 or the like, first, the compressor 41 makes the refrigerant be in a high-temperature and high-pressure state. The refrigerant in the high-temperature and high-pressure state is sent to the condenser 42 through the pipe 46. In the condenser 42, the refrigerant is liquefied by a cooling action of the low-temperature air sent from the blower fan 45. The refrigerant in the liquid state is sent to the capillary tube 43 through the pipe 46. In the capillary tube 43, the refrigerant is expanded and thereby changed to be in a low-pressure and low-temperature state. Then, this refrigerant is sent to the evaporator 44. In the evaporator 44, the heat generated in the CPU 36 is received by the refrigerant. As a result, the refrigerant evaporates to be changed to the gaseous state. The refrigerant in the gaseous state is sent to the compressor 41 again.

The above-described operation of the cooling device 40 cools the CPU 36. In this embodiment, by employing the cooling device 40 of a refrigeration cycle, the CPU 36 with a power consumption of, for example, approximately 60 W to 200 W can be sufficiently cooled.

In the cooling device 40 of this embodiment, the compressor 41, the condenser 42, and the blower fan 45 are placed at two-dimensionally different positions, and the longitudinal directions of the compressor 41 and the condenser 42 are placed in an L shape in a vicinity of the blower fan 45. This placement can make the two-dimensional size of the cooling device 40 compact, so that the cooling device 40 would not limit a layout of other components contained in the casing unit 30. Alternatively, the longitudinal directions of the compressor 41 and the condenser 42 may be placed in the L shape at a place other than the vicinity of the blower fan 45.

Specifically, the compressor 41 and the condenser 42 are relatively large among the components constituting the cooling device 40. Accordingly, if such large-size components are placed to protrude to a peripheral portion, the cooling device 40 occupies a large area in the casing unit 30 and limits the layout of the other components. Thus, by placing the longitudinal directions of the compressor 41 and the condenser 42 in the L shape, the two-dimensional size of the cooling device 40 becomes compact, and the protruding portion is eliminated.

The compressor 41 and the condenser 42 are components which are cooled by the blower fan 45. Accordingly, placing the compressor 41 and the condenser 42 in the L shape in the vicinity of the blower fan 45 also provides an advantage that a cooling effect of the blower fan can be made large.

The cooling device 40 is placed in a concentrated manner in a left rear end portion of the inside of the casing unit 30. Placing the cooling device 40 at such a position can prevent a harmful effect of the heat released from the cooling device 40 on the other electronic components such as the HDD 34. Here, the cooling device 40 may be placed at a place other than the left rear portion. That is, a place where the cooling device 40 is placed may be a right rear end portion, a left front end portion, or a right front end portion of the inside of the casing unit 30.

The places of the condenser 42 and the compressor 41 may be interchanged. That is, the compressor 41 is placed at a rear portion of the inside of the casing unit 30 in a manner that the longitudinal direction of the compressor 41 is parallel to a rear side face of the casing unit 30. In addition, the condenser 42 may be placed in the right side portion or the left side portion of the inside of the casing unit 30 in a manner that the longitudinal direction of the condenser 42 is parallel to the right or left side face of the casing unit 30.

Next, referring to FIGS. 2A and 2B, a structure of the computer 10 will be described with a focus on the blower fan 45. FIG. 2A is a perspective view showing a portion in which the cooling device 40 is incorporated in the computer 10, and FIG. 2B is a perspective view of the computer 10 as obliquely seen from below.

Referring to FIG. 2A, the condenser 42 is placed in the vicinity of the rear end portion of the inside of the casing unit 30. Moreover, the longitudinal direction of the condenser 42 is placed approximately parallel to the rear side face of the casing unit 30. Thus, the air blown on the condenser 42 by the blower fan 45 is heated to a high temperature by receiving the heat from the condenser 42. Thereafter, the heated air is expelled to the outside from the rear side face of the casing unit 30. Here, as described above, the places of the condenser 42 and the compressor 41 may be interchanged.

The compressor 41 is placed in the vicinity of the left end portion of the casing unit 30, and the longitudinal direction of the compressor 41 is placed approximately parallel to the left side face of the casing unit 30. Accordingly, the air blown on the compressor 41 by the blower fan 45 receives the heat of the compressor 41, and then is expelled to the outside of the casing unit 30.

As described above, the condenser 42 and the compressor 41, which generate the heat with the operation of the cooling device 40, are placed in the peripheral portion of the casing unit 30. Thus, the air which is blown by the blower fan 45 to be heated to the high temperature can be immediately expelled to the outside of the casing unit 30. Accordingly, this makes it possible to prevent the entire casing unit 30 from being heated to a high temperature by the heat generation of the condenser 42 and the compressor 41.

Referring to FIG. 2B, the blower fan 45 takes in the low-temperature outside air into the casing unit 30 through an intake vent 39 provided in a bottom face of the casing unit 30. The air, which cools the condenser 42 and the compressor 41, thereby being heated to the high temperature, is expelled to the outside through exhaust vents 37 and 38 provided respectively in the side faces of the casing unit 30. The intake vent 39 and the exhaust vents 37 and 38 are formed of a large number of slit-shaped holes provided in the casing unit 30.

By providing the exhaust vent 38 in the rear side face of the casing unit 30, the high-temperature air heated by receiving the heat of the condenser 42 is exhausted to the rear of the computer 10. Accordingly, since the heated air is not exhausted toward a user in front of the computer 10, the user can be prevented from getting injured, for example, getting burned. Alternatively, the air heated to a high temperature by receiving the heat of the condenser 42 may be expelled to the outside from the right side face or the left side face of the casing unit 30.

By providing the exhaust vent 37 in the left side face of the casing unit 30, the air, which cools the compressor 41, thereby being heated to a high temperature, is expelled to the outside from the left side face of the computer 10. On the other hand, a normal user operates a pointing device such as a mouse with his or her right hand. Accordingly, since the high-temperature air exhausted from the exhaust vent 37 does not touch the hand of the user using the mouse, the user can be prevented from getting burned. Alternatively, the exhaust vent 37 may be provided in the right side face of the casing unit 30.

As described above, the air exhausted from the cooling device 40 using the refrigeration cycle is at the high temperature of, for example, approximately 50° C. to 60° C. Accordingly, since the exhaust vents 37 and 38 through which the high-temperature air is exhausted are provided respectively in the left side face and the rear side face of the casing unit 30, the user does not touch the exhausted air. Thus, a constitution of a computer which is safe for a user can be obtained.

Referring to FIGS. 3A and 3B, the computer 10 will be described with a particular focus on a configuration of the pipes. FIG. 3A is a view of the computer 10 as seen from front, and FIG. 3B is a cross-sectional view of a portion in which the cooling device 40 is placed.

Referring to FIGS. 3A and 3B, the compressor 41, the condenser 42, the capillary tube 43, and the evaporator 44, which constitute the cooling device 40, are connected to one another via the pipes 46. The heat generated in the CPU 36 is transferred to the condenser 42 through the refrigerant flowing inside the pipes 46, thereby being released to the outside.

In this embodiment, at least one portion of the pipe 46A connecting the capillary tube 43 to the evaporator 44 is positioned above the evaporator 44. Moreover, at least one portion of the pipe 46B connecting the evaporator 44 to the compressor 41 is positioned above the evaporator 44. This configuration provides an advantage that the refrigerant in the liquid state is stored in the pipes 46A and 46B and the evaporator 44, and that the CPU 36 is cooled by the stored liquid refrigerant (the refrigerant in the liquid state).

Specifically, the pipes 46A and 46B are formed of a metal such as copper, for example, in a pipe form. At least the portions of these pipes are positioned above an upper face of the evaporator 44 which cools the CPU 36. While the cooling device 40 is operating, the refrigerant passes inside the pipes 46A and 46B. When the computer 10 is shut down and the cooling device 40 is stopped, the refrigerant in the liquid state remains in the pipes 46A and 46B and the evaporator 44. Then, when the computer 10 is started again, the evaporator 44 cools the CPU 36 by use of the liquid refrigerant remaining in the pipes 46A and 46B and the evaporator 44.

Specifically, when the computer 10 is started, the CPU 36 operates most actively and is heated. A reason for this is that the CPU 36 is set so as to operate actively at a startup of the computer in response to a user's demand for a faster startup of the computer.

It is desirable that the cooling device 40 start to operate and to cool the CPU 36 immediately in synchronization with the startup of the computer 10. However, actually, in some cases, there is a time difference between the startup of the computer 10 and that of the cooling device 40. Thus, if the CPU 36 operates actively and the cooling device 40 does not perform cooling immediately after the startup of the computer, the CPU 36 may be heated to an excessively high temperature. In this embodiment, to cope with this, the pipes 46A and 46B, through which the refrigerant is supplied to the evaporator 44 cooling the CPU 36, are positioned above the evaporator 44. Thus, when the cooling device 40 is stopped, the liquid refrigerant is stored in the pipes 46A and 46B and the evaporator 44. Even if the cooling device 40 is not operating in rebooting the computer, the CPU 36 is cooled for a certain period of time by the liquid refrigerant stored in the pipes 46A and 46B and the evaporator 44. Accordingly, it is possible to prevent the CPU 36 from being excessively heated in rebooting the computer.

In the above-description, both pipes 46A and 46B are positioned above the evaporator 44. However, only one of the pipes 46A and 46B may be positioned above the evaporator 44. In addition, by placing both pipes 46A and 46B above the evaporator 44, a larger amount of the liquid refrigerant is stored. Therefore, this placement provides an advantage that the above-described cooling effect becomes larger.

Referring to FIGS. 4A and 4B, details of the rotary compressor 41 employed as the compressor of this embodiment will be described. FIG. 4A is a plan view showing a structure of the rotary compressor 41, and FIG. 4B is a cross-sectional view of a pump section of the rotary compressor.

Referring to FIG. 4A, the rotary compressor 41 includes a motor section 50, and a pump section 51 driven by the motor section 50. The motor section 50 contains a motor rotated by a power supplied from a terminal 52. The pump section 51 is a section for compressing the refrigerant introduced from the outside, and is operated by a driving force of the motor section 50. The inlet section 48 is a section through which the refrigerant after expansion is introduced into the rotary compressor 41 from the outside. The outlet section 47 is a section through which the refrigerant compressed by the rotary compressor 41 is taken out to the outside. Moreover, each of the elements constituting the motor section 50 and the pump section 51 is contained in an approximately cylindrical case 57.

Referring to FIG. 4B, a structure of the pump section 51 will be described. The pump section 51 includes a cylinder 53 contained in the case 57, and a roller 56 which is contained in the cylinder 53 and which rotates. In the cylinder 53, a cylinder chamber 55 is provided between the cylinder 53 and the roller 56. In addition, in the roller 56, a shaft 62 having a circular cross section is provided. A position of the shaft 62 is fixed. Moreover, in the cylinder 53, a vane 54 is provided in order to partition the cylinder chamber 55 into a portion in which the refrigerant compressed is positioned and a portion in which the refrigerant uncompressed is positioned. The vane 54 is provided so as to be oscillatorily movable in a vertical direction.

An inner wall of the roller 56 is in contact with the shaft 62. Thus, the roller 56 rotates in a decentered manner in the cylinder 53, whereby the refrigerant introduced through the inlet section 48 is compressed. The refrigerant compressed in the cylinder chamber 55 is filled into the case 57 through a notch section 60 and expelled to the outside through the outlet section 47. The notch section 60 is a section made by cutting out a portion of the cylinder 53 in order to transfer the refrigerant in the cylinder chamber 55 to the case 57. Moreover, in order to facilitate a rotation of the roller 56, a lubricating oil is contained inside the case 57.

In this embodiment, the outlet section 47 through which the compressed refrigerant is discharged to the outside is provided above a rotation axis 58 of the rotary compressor 41. Here, the rotation axis 58 is a center of the shaft 62 and, in other words, a center of the case 57. This makes it possible to prevent the lubricating oil from being mixed into the refrigerant expelled to the outside through the outlet section 47.

To be more precise, as shown in FIGS. 1A and 1B, the rotary compressor 41 is horizontally oriented, located on one plane on which the condenser 42, the blower fan 45 and the like are mounted. Accordingly, the lubricating oil in the case 57 is positioned in a lower portion under an influence of gravity. Thus, if the outlet section 47 through which the refrigerant is taken out to the outside is provided in a lower portion of the rotary compressor 41, a large amount of lubricating oil may be mixed into the refrigerant taken out. If the large amount of lubricating oil is mixed into the refrigerant taken out, the amount of the lubricating oil in the rotary compressor 41 decreases. As a result of this, the function of the compressor may decrease and the CPU may not be sufficiently cooled. Accordingly, in this embodiment, the outlet section 47 is provided in an upper portion of the case 57. This prevents a large amount of lubricating oil from being mixed into the refrigerant discharged.

On the other hand, the inlet section 48 is placed in a portion of the case 57 which is lower than the rotation axis 58. This is because the cylinder chamber 55 is partitioned by the vane 54 as described previously.

Referring to FIGS. 5A and 5B, another embodiment of the cooling device 40 will be described. FIGS. 5A and 5B are views showing the cooling device 40 of the embodiment.

Referring to FIG. 5A, two blower fans 45A and 45B are provided here. Providing the two blower fans 45A and 45B in this way increases an amount of an air blown on a condenser 42. Accordingly, a cooling function of the cooling device 40 can be further improved. The two blower fans 45A and 45B are placed adjacently to each other here, but may be placed apart from each other. Moreover, three or more blower fans may be provided.

Referring to FIG. 5B, a pipe 46C connecting a compressor 41 to an evaporator 44 is in contact with a memory 49, here. Thus, this causes the refrigerant passing inside the pipe 46C to receive heat generated in the memory 49, and thereby the memory 49 is cooled. Although the memory 49 is cooled by the pipe 46C, here, electrical devices other than the memory can also be cooled by the pipe 46C. For example, the pipe 46C can cool a chip set controlled by a CPU 36, an element for controlling graphics, and the like.

Referring to FIG. 6, an operation of the computer 10 will be described with a focus on a cooling action on a CPU 36. Here, the microcomputer 59 controls rotations of the compressor 41 and a blower fan 45 based on information on a temperature of the CPU 36. With this configuration, the microcomputer 59 changes the numbers of rotations of the compressor 41 and the blower fan 45 depending on whether the temperature of the CPU 36 is low or the temperature thereof is high.

Specifically, as described previously, the heat generated in a heat-generating functional element such as the CPU 36 is received by the refrigerant via the evaporator 44 of the cooling device 40. In the cooling device 40, the refrigerant circulates in the evaporator 44, the compressor 41, the condenser 42, and a capillary tube 43, while repeating expansion and compression. In addition, the blower fan 45 blows air on the condenser 42, whereby the heat of the refrigerant is released to an outside. Furthermore, a motor incorporated in the compressor 41 is controlled by an inverter 61.

The above-described configuration of this embodiment makes it possible to maintain the temperature of the CPU 36 equal to or less than a certain temperature (for example, 70° C.). However, the amount of the heat generated in the CPU 36 is not constant. That is, the amount of the heat becomes larger as the CPU 36 operates more actively, and the amount of the heat becomes smaller as the CPU 36 operates less actively. Thus, the amount of the heat generated in the CPU 36 becomes so large temporarily, that a level of cooling performance of the cooling device 40 may become insufficient when rotational speeds of the motor provided in the compressor 41 and the blower fan are slow. Thereby, the temperature of the CPU 36 may increase. On the other hand, if the rotational speeds of the motor provided in the compressor 41 and the blower fan 45 are always set high in order to prevent this phenomenon, a temperature rise in the CPU 36 can be reduced, but a power consumption of the cooling device 40 may become large.

Accordingly, in this embodiment, the rotational speeds of the motor provided in the compressor 41 and the blower fan 45 are controlled depending on the temperature of the CPU 36. That is, the rotational speeds thereof are increased as the temperature of the CPU 36 increases. This makes it possible to keep the temperature of the CPU 36, for example, between 50° C. and 70° C. Details thereof are as follows.

The temperature of the CPU 36 is monitored by a sensor section (monitoring means) incorporated in the CPU 36 itself, and temperature information indicating the temperature of the CPU 36 is transmitted to the microcomputer 59 (controlling means). The microcomputer 59 controls the numbers of revolutions of the inverter 61 and the blower fans 45.

For example, in a case where the temperature of the CPU 36 is desired to be kept a temperature between 50° C. and 70° C. as described previously, the numbers of revolutions of the inverter 61 and the blower fan 45 are controlled by the microcomputer 59 as follows.

When the temperature of the CPU 36 is less than 55° C. (a first temperature), the numbers of revolutions of the inverter 61 and the blower fan 45 are maintained constant based on an instruction of the microcomputer 59. In this case, the numbers of rotations are kept within a range, for example, at which the blower fan 45 and the compressor 41 operate, generating only low operation noise.

When the temperature of the CPU 36 is 55° C. to 65° C. (that is, when it is higher than the above-described first temperature), the numbers of rotations of the inverter 61 and the blower fan 45 are increased in proportion to an increase of the temperature of the CPU 36. Thus, the level of the cooling performance of the cooling device 40 is adjusted depending on a change in the temperature of the CPU 36 within a range of 55° C. to 65° C. Accordingly, the temperature of the CPU 36 can be controlled to be 50° C. to 70° C. as described previously.

When the temperature of the CPU 36 is equal to or more than 65° C. (a second temperature), the numbers of rotations of the inverter 61 and the blower fan 45 are maintained constant. That is, the motors provided in the compressor 41 and the blower fan 45 are rotated respectively at the maximum rotational speeds. This can suppress the increase of the temperature of the CPU 36.

The above is the description of the operation of the computer 10 in which the CPU 36 is cooled.

According to the cooling devices for electronic instruments of the present invention, a size of a cooling device using a refrigeration cycle can be reduced. Specifically, a condenser and a compressor constituting the cooling device are relatively large components. Accordingly, the size of the entire cooling device can be made compact by placing longitudinal directions of the condenser and the compressor, which are large as described above, in an L shape.

In addition, in the present invention, pipes connected to the evaporator are placed above the evaporator. As a result, a liquid refrigerant is stored in the evaporator or/and the pipes. Accordingly, even when the cooling device is not operating, heat generated in a heat generating body such as a CPU can be absorbed by the liquid refrigerant stored in the evaporator or/and the pipes.

Moreover, in the present invention, a refrigerant is taken out of a rotary compressor placed horizontally through an inlet section. The inlet section is positioned above a rotation axis of the rotary compressor. Accordingly, it possible to prevent a lubricating oil used in the rotary compressor from being mixed into the refrigerant taken out.

In an electronic instrument of the present invention, the cooling device using a refrigeration cycle is contained in the casing. Thereby, even in a case where the electronic instrument such as a notebook computer includes a CPU generating a large amount of heat, it is made possible to sufficiently cool the CPU.

Moreover, in the electronic instrument of the present invention, the longitudinal directions of the condenser and the compressor of the cooling device are placed approximately parallel respectively to side faces of the casing unit. Accordingly, since the condenser and the compressor, which are relatively large components, can be compactly contained in the electronic instrument, a space in the casing which is occupied by the cooling device can be reduced.

Furthermore, in an electronic instrument of the present invention, a level of cooling performance of the cooling device can be controlled depending on a change in a temperature of the functional element contained in the casing unit. Accordingly, since the functional element can be cooled just enough, the functional element can be cooled sufficiently, while a power for cooling the functional element can be saved. 

1. A cooling device for an electronic instrument, the cooling device comprising: compressing means which compresses a refrigerant; condensing means which condenses the refrigerant compressed by the compressing means into a liquid by releasing heat from the refrigerant to an outside; expanding means which expands the refrigerant condensed into the liquid by the condensing means; evaporating means which evaporates the refrigerant expanded by the expanding means by receiving heat from a semiconductor element; and blowing means which blows air, wherein the compressing means and the condensing means are placed at two-dimensionally different positions, and longitudinal directions of the condensing means and the compressing means are placed in an L shape.
 2. The cooling device for the electronic instrument according to claim 1, wherein the blowing means blows air on the condensing means and the compressing means.
 3. The cooling device for the electronic instrument according to claim 1, wherein the compressing means is a rotary compressor.
 4. The cooling device for the electronic instrument according to claim 1, wherein the compressing means comprises an inlet section through which the refrigerant is introduced from the evaporating means, and an outlet section through which the refrigerant is discharged to the condensing means, and the outlet section is placed at a position closer to the condensing means than the inlet section.
 5. A cooling device for an electronic instrument, the cooling device comprising: compressing means which compresses a refrigerant; condensing means which condenses the refrigerant compressed by the compressing means into a liquid by releasing heat from the refrigerant to an outside; expanding means which expands the refrigerant condensed into the liquid by the condensing means; evaporating means which evaporates the refrigerant expanded by the expanding means by receiving heat from a semiconductor element; and blowing means which blows air, wherein the compressing means, the condensing means, and the blowing means are placed at two-dimensionally different positions, and the compressing means and the condensing means are placed in a vicinity of the blowing means.
 6. The cooling device for the electronic instrument according to claim 5, wherein the blowing means blows air on the condensing means and the compressing means.
 7. The cooling device for the electronic instrument according to claim 5, wherein the compressing means is a rotary compressor.
 8. The cooling device for the electronic instrument according to claim 5, wherein the compressing means comprises an inlet section through which the refrigerant is introduced from the evaporating means, and an outlet section through which the refrigerant is discharged to the condensing means, and the outlet section is placed at a position closer to the condensing means than the inlet section.
 9. The cooling device for the electronic instrument according to claim 5, wherein longitudinal directions of the condensing means and the compressing means are placed in an L shape.
 10. A cooling device for an electronic instrument, the cooling device comprising: compressing means which compresses a refrigerant; condensing means which condenses the refrigerant compressed by the compressing means into a liquid by releasing heat from the refrigerant to an outside; expanding means which expands the refrigerant condensed into the liquid by the condensing means; and evaporating means which evaporates the refrigerant expanded by the expanding means by receiving heat from a semiconductor element, wherein at least a portion of a pipe connected to the evaporating means is positioned above the evaporating means.
 11. The cooling device for the electronic instrument according to claim 10, wherein the pipe is a pipe connecting the compressing means to the evaporating means or/and a pipe connecting the evaporating means to the expanding means.
 12. The cooling device for the electronic instrument according to claim 10, wherein when the compressing means stops, a liquid refrigerant remains in the evaporating means and/or the pipe, and the evaporating means receives heat from the semiconductor element by using the remaining liquid refrigerant.
 13. A cooling device for an electronic instrument, the cooling device comprising: compressing means which compresses a refrigerant; condensing means which condenses the refrigerant compressed by the compressing means into a liquid by releasing heat from the refrigerant to an outside; expanding means which expands the refrigerant condensed into the liquid by the condensing means; and evaporating means which evaporates the refrigerant expanded by the expanding means by receiving heat from a semiconductor element, wherein the compressing means, the condensing means, and the evaporating means are placed at different positions on one plane, the compressing means comprises a rotary compressor placed horizontally on the one plane, the rotary compressor comprises an inlet section through which the refrigerant is introduced, and an outlet section through which the refrigerant is discharged, and the outlet section is provided above a rotation axis of the rotary compressor.
 14. A cooling device for an electronic instrument, the cooling device comprising: compressing means which compresses a refrigerant; condensing means which condenses the refrigerant compressed by the compressing means into a liquid by releasing heat from the refrigerant to an outside; expanding means which expands the refrigerant condensed into the liquid by the condensing means; and evaporating means which evaporates the refrigerant expanded by the expanding means by receiving heat from a semiconductor element, wherein the compressing means, the condensing means, and the evaporating means are placed at different positions on one plane, the compressing means comprises a rotary compressor placed horizontally on the one plane, the rotary compressor comprises an inlet section through which the refrigerant is introduced, and an outlet section through which the refrigerant is discharged, and the inlet section is provided below a rotation axis of the rotary compressor.
 15. An electronic instrument having a casing unit containing a functional element which operates while generating heat, the electronic instrument comprising: a cooling device contained in the casing unit, the cooling device cooling the functional element by using a refrigeration cycle.
 16. The electronic instrument according to claim 15, wherein the cooling device takes in outside air through a bottom face of the casing unit, and the air absorbs heat generated in the functional element, and thereafter is expelled from a rear side portion or/and a side portion of the casing unit.
 17. An electronic instrument having a casing unit containing a functional element which operates while generating heat, the electronic instrument comprising: a cooling device contained in the casing unit, the cooling device comprising compressing means which compresses a refrigerant, condensing means which condenses the refrigerant compressed by the compressing means into a liquid by releasing heat from the refrigerant to an outside, expanding means which expands the refrigerant condensed into the liquid by the condensing means, evaporating means which evaporates the refrigerant expanded by the expanding means by receiving heat from a semiconductor element, and blowing means which blows air, wherein longitudinal directions of the condensing means and the compressing means are placed approximately parallel respectively to side faces of the casing unit.
 18. The electronic instrument according to claim 17, wherein the condensing means is placed in a vicinity of a rear portion of the casing unit, and the longitudinal direction of the condensing means is placed approximately parallel to a rear side face of the casing unit, and the compressing means is placed in a vicinity of any of a right side portion and a left side portion of the casing unit, and a longitudinal direction of the compressing means is placed approximately parallel to any of right and left side faces of the casing unit.
 19. The electronic instrument according to claim 17, wherein the condensing means is placed in a vicinity of any one of a right side portion and a left side portion of the casing unit, and the longitudinal direction of the condensing means is placed approximately parallel to any of right and left side faces of the casing unit, and the compressing means is placed in a vicinity of a rear portion of the casing unit, and the longitudinal direction of the compressing means is placed approximately parallel to a rear side face of the casing unit.
 20. The electronic instrument according to claim 17, wherein the blowing means takes in outside air through a bottom face of the casing unit, and the air passes through the condensing means, and thereafter is expelled to an outside from a rear side of the casing unit.
 21. The electronic instrument according to claim 17, wherein the blowing means takes in outside air through a bottom face of the casing unit, and the air passes through the compressing means, and thereafter is expelled to an outside from any one of a left side and a right side of the casing unit.
 22. An electronic instrument having a casing unit containing a functional element which operates while generating heat, the electronic instrument comprising: a cooling device contained in the casing unit, the cooling device comprising compressing means which compresses a refrigerant, condensing means which condenses the refrigerant compressed by the compressing means into a liquid by releasing heat from the refrigerant to an outside, expanding means which expands the refrigerant condensed into the liquid by the condensing means, evaporating means which evaporates the refrigerant expanded by the expanding means by receiving heat from a semiconductor element, and blowing means which blows air; monitoring means which monitors a temperature of the functional element; and controlling means which controls a cooling power of the cooling device based on an output from the monitoring means.
 23. The electronic instrument according to claim 22, wherein, based on the output from the monitoring means, the controlling means changes the number of rotations of a motor provided in the compressing means or/and the number of rotations of the blowing means.
 24. The electronic instrument according to claim 23, wherein the controlling means increases the number of rotations of the motor or/and the number of rotations of the blowing means based on the output from the monitoring means, the output indicating that the temperature of the functional element is higher than a first temperature, and the controlling means maintains constant the number of rotations of the motor or/and the number of rotations of the blowing means based on the output from the monitoring means, the output indicating that the temperature of the functional element is higher than a second temperature. 